be sure to have mttr support in your kernel and a fairly new version of X

then press ctrl-f12 to speed dosbox up. once you hit the roof use ctrl-f8 to skip frames so you can speed dosbox even more up.

But that mttr support is really important. as at my place X was using most of the cpu time instead of dosbox.

mttr support ???? what is that ?

I'm sorry but i really dont know what that is

I can configure and recompile my kernel but i would like a bit more information of what mttr support is please

If I dont know what it is, I dont even know where to find the option to enable it in my kernel 😜

you might allready have it though. I just "forgot" to enable it on my kernel

it's in cpu options page the one where you can specify athon or pentium 1

it's some sort of memory mapping and register support.
it makes the video memory (of vidcard) better accesable to X

quote from kernel :

" On Intel P6 family processors (Pentium Pro, Pentium II and later) │
│ the Memory Type Range Registers (MTRRs) may be used to control │
│ processor access to memory ranges. This is most useful if you have │
│ a video (VGA) card on a PCI or AGP bus. Enabling write-combining │
│ allows bus write transfers to be combined into a larger transfer │
│ before bursting over the PCI/AGP bus. This can increase performance │
│ of image write operations 2.5 times or more. Saying Y here creates a │
│ /proc/mtrr file which may be used to manipulate your processor's │
│ MTRRs. Typically the X server should use this.
"
But just look at dmesg output for mtrr

my one :
qbix@Het-Beest:~$ dmesg | grep mtrr
mtrr: v1.40 (20010327) Richard Gooch (rgooch@atnf.csiro.au)
mtrr: detected mtrr type: Intel

Well, I checked with "dmesg | grep mtrr" and I got this:

mtrr: v1.40 (20010327) Richard Gooch (rgooch@atnf.csiro.au)
mtrr: detected mtrr type: Intel

Looks like its ON... the only thing that is a bit strange is that i do not have Intel! I have an AMD Athlon ! Does this make a difference ?

I've got an athlon as well 😀

The problem with X is that it takes many resources.
I'm glad X and nvidia are good friends.

as a tip to decrease the cpu usage of x :

create a configfile and set keepsmall=true (reduces X by factor 4)

decrease colordepth of X to 16 bit. (it seemed to help me for another 10 %)

run game fullscreen. (alt-enter)

look in the XFree86.0.log for any strangeness about your videocard
especially
(WW) are evil .